Ferruginous Hawk

by John Shackford

Recently Bill Diffin relayed to me some interesting information about the Ferruginous Hawk (Buteo regalis).  The Ferruginous Hawk has small feet for its size.  One of the references was from the Arizona-Sonora Desert Museum website (desertmuseum.org/visit/rff_ferruginous.php), which stated that small feet “aids them hunting burrowing mammals.  They make a ‘fist’ and punch it into the dirt of a burrow, and pull out the animal.”  Bill sent several additional references backing up this statement. A related behavior is that Ferruginous Hawks do not mind sitting on the ground for long periods of time, especially in prairie dogtowns, waiting for a mammal to show evidence of itself.  They take many pocket gophers, and, although they usually do not see the animal itself, they see the dirt moving along a burrow that indicates a gopher underground.  No doubt it is then they leap with balled-up fists to catch prey.

I have mentioned before that in 1986 I studied 5 rare nesting species in Cimarron County.  The Ferruginous Hawk was 1 of the species.  On 1 occasion I stayed half a day in a blind, built by Bill Voelker (whom many of you know), photographing at the nest of a light-plumaged (normal) male and dark-plumaged female, the first such pairing photographed in Oklahoma.  In one instance I observed the male bring a pocket gopher and drop it to the female at the nest, leave, and in less than 4 minutes return with another pocket gopher.  Pretty efficient prey gathering!

The Ferruginous Hawk is the largest Buteo hawk we have, at 23 inches.   It is brown on the back and whitish on the breast with some streaks on the flank.  The tail may have a suggestion of red, but not as red as a Red-tailed Hawk.  The tell-tale mark is legs with brown feathers down to the toes.  In flight the brown feathered legs form a V against the light breast.  There is also a dark phase; seen in flight, the underwing has whitish on the primaries and secondaries.  And the most important distinguishing feature is a tail that is a little lightish overall when seen from underneath, but does not have a lightish band across the under-tail like the dark phase of the Rough-legged Hawk has.

Two falconers and I once had an interesting conversation with a local rancher in Cimarron County.  We were talking about eagles and the resident said that there were 3 kinds of eagles locally.  The three of us assured her that there were only 2 kinds of eagles, but she was very insistent there were 3—the Bald Eagle, the Golden Eagle, and the Spanish Eagle—which she said was slightly smaller than the other 2.  We let the discussion drop after a while, but she never gave in.  Many years later it hit me—the “Spanish Eagle” was the dark form of the Ferruginous Hawk, so everyone was right!  I had even seen a “Spanish Eagle” (local name) in the lady’s “neighborhood.”

In winter the Ferruginous Hawk comes across about the western 1/3 of the state, and on rare occasions we get 1 on our Christmas Bird Count (CBC).  Patti and Brian Muzny have found 1 for the last 2 years on our CBC, perhaps the same bird I am guessing.  Congratulations to them for great work.

In Oklahoma the Ferruginous Hawk nests primarily in Cimarron County and some in Texas County, but in the not too distant past they have even been found nesting as far east as the main body of the state.  They build a huge nest reminiscent of a Bald Eagle nest, and usually place it in a low tree or on a windmill tower; in some areas other than Oklahoma they will nest on the ground.  I once found an active nest on a windmill tower that was missing its rotary blades.  One day when I was checking up on it, the nest was gone from the tower.  I was puzzled until I noticed “sticks” and broken eggs beneath the tower.  I picked up several of the sticks, and they turned out to be the dead stalks that once held the blooms of yucca plants.  To my surprise these stalks felt lighter than balsam wood.  As a result, I have little doubt that on a windy Oklahoma day, the nest made primarily of yucca stalks simply blew off the windmill tower, no match for the Oklahoma wind.